Aptitude

A train 120m long passes a pole in 12 seconds.

here, distance travelled by train=length of train= 120m

time taken by train= 12 seconds

then speed of train=distance travelled by train/time taken by train

speed of train= 120m/12sec =10 m/sec

when train passes a 130 m long platform,

distance travelled by train= length of train + length of platform=120+130=250 m

time taken by train to pass 130 m long platform=distance covered by train / speed of train

time taken by  the train= 250 / 10= 25 seconds